Slave Morality:Corporal Mortification, Frailocracy and the concept of Indulgence (Induluhensya)

Slave Morality is a part of Nietzche's Atheism. Slave Morality is people taking responsibility for suffering because they think that suffering will ultimately lead to their liberation. This is the reason why people have a tendency to attribute power to priests and friars. These religious people make us realize how sinful we are and thus people are encouraged to suffer more to reach salvation. Ways that are encouraged by giving power to priests and friars are corporal mortification and indulgence (induluhensya). Corporal Mortification made popular by the opus dei religion where in people consciously inflict harm on themselves and indulgence which was famous in the philippines during the spanish occupation. Indulgence is when people pay or give donations to the church in exchange for certain number years of salvation from sin.

I'm trying to connect these concepts but i'm not sure if it's actually worth studying. Can someone please shed more light on the aforementioned topics. Also, if you guys have any interesting topics related to philosophy of religion that you can share with me, please do share it. I really need a topic for my paper and i can't seem to think of any.

Thanks!